Positive correlation of plasma PCSK9 levels with HbA1c in patients with type 2 diabetes.

Background: Proprotein convertase subtilisin/kexin type 9 (PCSK9) has been demonstrated to be involved in not only lipid metabolism but also glucose homeostasis. Glycated haemoglobin (HbA1c ) is a 'gold standard' for monitoring long-term glycaemic control. However, the correlation of plasma PCSK9 levels with HbA1c remains undetermined.

Methods: We consecutively enrolled 805 subjects undergoing coronary angiography, including 176 patients with type 2 diabetes mellitus (T2DM) and 629 non-diabetic patients. The baseline characteristics were collected, and serum PCSK9 level was assessed by ELISA. Univariable regression analysis and multiple-variable regression analysis were used to examine the associations of PCSK9 with HbA1c . Furthermore, the HbA1c was compared across the tertiles of PCSK9 levels. And also, PCSK9 levels were compared in poorly controlled (HbA1c  ≥ 7.0%) and well-controlled (HbA1c  < 7.0%) patients with T2DM.

Results: PCSK9 levels were positively correlated with low-density lipoprotein cholesterol in both T2DM and non-T2DM. Univariable regression analysis revealed a positive association between PCSK9 and HbA1c in patients with T2DM (β = 0.255, p = 0.001) but not in patients without diabetes (β = 0.061, p = 0.128). Multiple-variable regression analysis exhibited that PCSK9 was independently correlated with HbA1c in T2DM after adjustment for traditional atherosclerotic risk factors (β = 0.197, p = 0.020). Moreover, HbA1c level was higher in patients with the highest tertile of PCSK9 than that in the lowest tertile (p = 0.042). Additionally, higher levels of PCSK9 were found in poorly controlled group compared with the well-controlled group (p = 0.029).

Conclusions: Data suggest a positive correlation of PCSK9 levels with HbA1c in patients with T2DM but not in patients without T2DM, indicating a potential role of PCSK9 in T2DM. Copyright © 2015 John Wiley & Sons, Ltd.